Nanocasting and Direct Synthesis Strategies for Mesoporous Carbons as Supercapacitor Electrodes

The flexible construction of electrode materials performs important functions in significantly enhancing the electrochemical properties of both energy storage and conversion devices. There is an increasing demand, not only for the current, but also the near-future energy field, where both high energy and power densities are necessary for the fabricated electrode materials. Carbon based nanoporous electrode materials demonstrate diverse superiority with respect to their application in the electrochemical capacitors (i.e., supercapacitors) industry. The striking characteristics of mesoporous carbons include abundance in raw materials, sustainability, good conductivity, excellent heat and chemical resistance, good workability, and lightweight nanostructure. Recently, various mesoporous carbons have increasingly been applied in the energy storage field because of their intrinsic open pore structure as well as high surface areas. However, the relationships between the synthesis strategies and the product structure and the structure and the supercapacitive properties of mesoporous carbons have not been comprehensively reviewed in the literature. Here, we focus on the progress made toward the construction of mesoporous carbons, with special emphasis on the state-of-the-art developments that have been able to achieve better management of pore networks and porosity, in addition to the improved filter of low cost and readily available carbon precursors and catalysts. The synthesis strategies used to produce the mesoporous carbon materials are summarized and the necessary synthesis conditions, the structural features of the resulting mesoporous carbons, and the supercapacitive properties are presented using a series of examples. Besides, some foreseeable challenges are presented for better exploitation of diverse mesoporous carbon materials with tunable pore networks and the expansion of supercapacitor markets. This review provides guidelines for those who work on mesoporous carbon materials about controlling their structure and morphology and those who focus on energy storage devices about the enhancement of the energy and power densities.